An advantage of using hollow-stem augers is what?

• A. no drilling fluid is used, eliminating contamination by drilling fluid additives
• B. faster penetration in hard rock
• C. lower equipment cost
• D. easier retrieval of samples

Answer: (A)

Hollow-stem augers are designed so the sample can be taken up through a central hollow path, minimizing contact with drilling fluids. This means samples can be retrieved with little to no mud or additives interacting with them, reducing the risk of contamination from drilling fluids. In practice, some air or minimal lifting methods may be used, but the key advantage is cleaner, less-contaminated samples because drilling fluids don’t circulate through the sample zone. Other benefits like faster penetration in hard rock or lower equipment cost aren’t inherent advantages of hollow-stem augers, and while easier sample retrieval can occur, the primary value is avoiding drilling-fluid contamination.